Making AR Pistol Reliable

[Joeywhat]

I'm seriously considering an AR pistol for my next build...I was dead set on a 10.5"/11.5" setup until I tried out a 7" pistol the other day...holy hell was that thing awesome!

My main concern with going to a pistol length barrel/gas system was reliability, I heard they just don't run. But this one did...and it was dry as a bone...and I was shooting Wolf.

So I'm off to build my own. 7" barrel, full length buffer tube with some sort of foam cover, KX3 out front and an either 9" or 10" free float tube with top rail, that covers most of the KX3.

What should I be looking for to make sure this thing runs? The one I shot had a Rainier Arms barrel, BCM BCG, and I think a Vltor upper receiver. Receiver extension was Spikes, it was running the ST-2 buffer, or whatever their version of an H2 buffer is.

For those that run 7" AR's, does yours run? If yes what parts are you using? For those that know more then I do, what are the things to look for to build a reliable pistol?

[Just_Plain_T.]

For those that run 7" AR's, does yours run? If yes what parts are you using?

Personally, I love my 7" AR. However I have noticed some users experiencing failures to feed when I let others try it. It's never happened to me before, and seems to be a matter of how it's held.

I'm using just the standard Spike's pistol lower as assembled and shipped by them to my FFL. However, if I was to be honest, I'd say that it's not 100% reliable, because other users (not all, just some) can create a problem. Based on my friends when we get in a group shooting, I'd say about half of them run into occasional FTFs, while the other half have never had issues.

[Wellman00]

I have a 7 1/2 and have noticed that it is much more finicky about the ammo and buffer combo than any other length I own. So far I have gotten 100% reliability with Full Power 5.56 (XM-193) ammo and H-buffer. I can also get 95% +/- reliability with wolf, tula or federal .223 ammo swapping in a standard carbine buffer. I am running a DPMS barrel with Ned's chamber reamer used on it making it OK to use 5.56. (Yeah, I know that I removed the Chrome in the chamber throat area). Also, Heavy Carrier and upgraded BCM extractor spring and O-ring on Bolt. Also a Levang Break and the RR pistol tube and standard carbine spring. It appears overgassed by the ejection pattern with my full power combo, but works wonderfully. Experimented with an H-2 buffer and it created reliability problems with the XM and wouldn't cycle half the time with the other ammo. Experiment (Safely) and Have Fun. That's what this sport is all about.